ISRO successfully launches PSLV with four satellites
By Venkatachari Jagannath | 10 Jan 2007
At 9.23 am this morning (10 January, 2007) the Rs80 crore PSLV, India's most successful space programme vehicle, was launched into orbit from Sriharikota in Andhra Pradesh.
Sriharikota: "10, 9, 8, 7…..3, 2, 1 ignition!", the count down had started for the tenth flight of India's space workhorse, the Rs80-crore Polar Satellite Launch Vehicle (PSLV). The launch conditions were perfect. The sky was clear, sparsely peppered with white clouds.
PSLV C7 blasted off the first launch pad at the Satish Dhawan Space Centre, SHAR, Sriharikota, Andhra Pradesh, along with its four payloads – two Indian and two overseas.
The Indian satellites are the 680kg remote sensing satellite Cartosat-2 and the 550kg space capsule recovery experiment (SRE 1) while the two overseas payloads are the Indonesian 56kg Lapan-Tubsat, an earth observation satellite, and an Argentinan 6kg nanosatellite, the Pehuensat-1, which will be used for education and scientific research.
It was a sight to behold when the 44.4-metre high, 295-tonne PSLV, with six strap-on motors hugging the mother rocket, kissed goodbye to the earth station and rose with a huge orange fire in its tail towards outer space.
The rocket's ascendance for the naked eye seemed slow though the vehicle was escaping the earth's gravity at a great speed.
19.32 minutes after lift off PSLV had slung its entire luggage into a 637 km high polar sun-synchronous orbit (SSO). India's Cartosat 2 was the first to be ejected and Pehuensat 1, SRE 1 and Lapan-Tubsat followed.
"It is a perfect mission. Everything went as planned. I can even challenge others to do a better job," declared a beaming G Madhavan Nair, chairman, Indian Space Research Organisation (ISRO).
He said president Dr A P J Abdul Kalam and prime minister Dr Manmohan Singh had conveyed their congratulations to the entire ISRO team for the success. "The president wanted to be kept informed on the progress of the SRE," he added.
Denying any pressure to perform after the failure of the geo-synchronous launch vehicle F 02 (GSLV F 02) last July, Nair said, "The launch was planned two years ago. After the GSLV F 02 failure we rechecked our entire quality check systems and have taken several corrective actions."
One such action, according to ISRO officials, is the burning of one first-stage engine at random. "Even though the burnt engine cannot be used in a launch vehicle, we do that as a quality checking parameter, " they said.
Immediately after the payloads were ejected into the orbit, the Spacecraft Control Centre at Bangalore with the help of ISTRAC network of stations at Bangalore, Lucknow, Mauritius, Bearslake (Russia), Biak (Indonesia) and Svalbard in Sweden began monitoring the satellite's health.
With this successful launch ISRO has ushered in 2007 in grand style. The launch also has a couple of firsts to its credit:
- For the first time ISRO's workhorse, the PSLV, has carried four payloads at the same time.
- For the first time in ISRO's history, a space recovery capsule was sent in to orbit, and,
- for the first time a dual launch adaptor was used in the launch vehicle
Compared to its previous flight, today's PSLV C7 carried a lower payload. In May 2005, PSLV C6 had carried a payload of 1,602 kg (1,560 kg Cartosat 1 and 42kg Hamsat) and delivered the same into a 620 km polar SSO.
This time the vehicle configuration has undergone a slight change. The modifications include: use of Dual Launch Adopter (DLA) to carry two large satellites, reduction of propellants from 2.5 tonnes to 2 tonnes in the fourth stage because of a lesser payload, incorporation of a video imaging system to capture payload and DLA separation events, an altitude based launch wind biased steering programme during Open Loop Guidance, deletion of secondary injection thrust vector control (SITVC) system for one of the air lift strap-ons, and reduction of first stage SITVC injectant by 500 kg.
The second Cartosat
Though weighing 880kg less than its first edition, Cartosat 2 (cost Rs180 crore) is a state of art satellite carrying panchromatic camera that takes black and white pictures.
The imagery will have a spatial resolution of slightly less than one metre. The camera covers a swath of around 9.6 km. Cartosat 2 also carries a solid-state recorder with a 64-giga bit capacity to store the images shot by its camera to be transmitted to the ground station as and when visibility permits.
The data it would transmit will be used in cartography at cadastral level, urban and rural infrastructure development and management as well as land information system, geographical information system.
With a life expectancy of five years, Cartosat 2 will make 14 orbits per day and would cross the equator at 9.30 am.
After the latest launch, India has a total of seven remote sensing satellites orbiting the earth viz IRS-1C, IRS-1D, Oceansat 1, TES, Resourcesat 1, Cartosat 1 and Cartosat 2. According to ISRO, the forthcoming remote sensing satellites are Oceansat 2 carrying ocean colour monitor and Ku-band pencil beam scatterometer and Radar Imaging Satellite (Risat) and Resourcesat 2.
The interesting payload
What makes PSLV C7 historic is the Rs30 crore, 550 kg bell-shaped space recovery capsule that will demonstrate the technology of orbiting platforms for performing experiments in microgravity conditions and its recovery.
As and when the SRE mission is completed successfully, India will joint a select club of nations that have the technology to send and receive vehicles above the atmosphere.
The experiment assumes importance in the wake of ISRO talking about manned space mission.
The SRE will provide important technology inputs in navigation guidance and control during the re-entry phase, hypersonic aerothermodynamics for reusable thermal protection system, recovery through deceleration and floatation besides acquisition of basic technology for reusable launch vehicles.
The capsule, which is expected to be in orbit for 13-30 days at 635 km, polar SSO, carries two payloads — an isothermal heating furnace and a biomimetic experiment. The first will be used for conducting metallurgical experiments while a biomimetic experiment will be operated to perform biomimetic synthesis, say ISRO officials.
Prior to its deorbiting, the space capsule will be placed in an elliptical orbit. Later it will be reoriented and a deboost rocket fired to make it re-enter the earth's atmosphere.
According to ISRO officials, closed loop guidance system is employed during deboosting and coasting phases leading to the capsule's recovery.
After re-entering the atmosphere, the capsule will be slowed down by aerodynamic braking and a parachute system will reduce further the touch down velocity.
The capsule will splash into Bay Bengal 140 km east of Sriharikota. Thanks to its floatation system, the capsule will float till its recovery by the Indian navy.
